Note: Descriptions are shown in the official language in which they were submitted.
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HYDROFORMING APPARATUS AND METHOD OF ASSEMBLING SAME
Related Application
[0001] The present application claims priority to all the benefits from
US provisional application No. 60/425,273, filed November 12, 2003.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to hydroforming apparatuses and
methods therefore. More specifically, the illustrated embodiments of the
present
invention relate to the connection between hydroforming presses and
hydroforming
die assemblies and methods therefore.
2. Description of the Related Art
[0003] Hydroforming is a forming process in which one or more
hydroforming presses are used to shape a blank disposed within a hydroforming
die
assembly. Hydroforming presses are coupled to hydroforming die assemblies to
provide a force exertion. In the prior art, connecting rods are threaded
directly into a
hole in the die assemblies making connection between die halves and
hydroforming
presses difficult and time consuming, and requiring excessive manpower.
SUMMARY OF THE INVENTION
According to one aspect of the invention, there is provided a hydroforming
apparatus comprising a hydroforming die member and a hydroforming press having
a housing. A fastener assembly comprising a fastener having a shaft
terminating at
a shoulder is used to connect the die member and housing. The shoulder forms a
head. A spacer is disposed about the fastener for separating the die member
and
housing a specified distance. The fastener is secured to the press housing at
one end
of the shaft and the shoulder of the fastener is received within a slot formed
in the
die member for connecting the die member and press.
According to another aspect of the invention, there is provided a method of
attaching a hydroforming press to a hydroforming die member comprising:
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providing a hydroforming die member; providing a hydroforming press having a
housing; providing a fastener assembly comprising a fastener having a
longitudinal
axis and a shaft terminating at a shoulder which forms a head. A spacer is
disposed
about the fastener and a nut is attached to the shaft of the fastener. The is
also
included the step of providing the die member with a slot configured to
receive the
shoulder in a direction that is transverse to the longitudinal axis of the
fastener. Also
included are the steps of providing a spacer disposed about the fastener;
securing the
shaft of the fastener to the housing; and positioning the shoulder of the
fastener
within the slot in the die member by moving the shoulder and the fastener in a
direction that is transverse to the longitudinal axis of the fastener.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Advantages of the present invention will be readily
appreciated as the same becomes better understood by reference to the
following
detailed description when considered in coimection with the accompanying
drawings
wherein:
[0005] FIG. 1 is plan view of a die assembly of a hydroforming
apparatus in accordance with one illustrated embodiment of the present
invention
with the upper die partially cut away and showing a press housing of a
hydroforming
press of the hydroforming apparatus removably coupled to the lower die member;
[0006] FIG. 2 shows a cross-sectional side view of the hydroforming
apparatus through line 2-2 in FIG. 1 and showing the tubular blank within the
apparatus;
[0007] FIG. 3 is a cross-sectional view through line 3-3 of FIG. 1;
[0008] FIG. 4 is a cross-sectional view of a fastener used in FIG. 1;
[0009] FIG. 5 is an enlarged perspective view of a portion of the lower die
member of FIG. 1 showing a slot therein and showing a portion of the fastener
in
exploded relation therewith;
[00010] FIG. 6 is a view similar to FIG. 5 except showing another
illustrative embodiment of a slot formed in a lower die member; and
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[00011] FIGS. 7 and 8 are perspective views of the press housing of
FIG. 1 and a fastener assembly mounted therein.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[00012] FIGS. 1-3 show an illustrative embodiment of an apparatus 10
according to one aspect of the present invention for hydroforming a tubular
metal
blank 12. The hydroforming apparatus 10 includes a hydroforming die assembly
14
and a pair of hydroforming presses 16, 18 mounted on opposite sides of the die
assembly 14. The die assembly 14 includes an upper die member 19 and a lower
die
member 21. The hydroforming presses 16 and 18 are removably and replaceably
attached to lower die member 21 through the use of fasteners 24 having heads
33
and shafts 30 that can be lowered into slots 28 to connect the presses 16 and
18 to
the lower die member 21 once the fasteners 24 are tightened. The presses 16
and 18
are then removable by loosening the fasteners 24 and then raising the
fasteners 24 to
disengage the heads 33 and shafts 30 from the slots 28. This configuration
facilitates the connection and disconnection between the hydroforming presses
and
die members.
[00013] The upper and lower die members 19, 21 are constructed of a
metallic material such as steel and are shaped to include respective die
surfaces 41,
42. The die surfaces 41, 42 cooperate to form a die cavity 44 when the die
members 19, 21 are in their closed position (see FIG. 1). The die cavity 44
forms a
continuous passageway that extends from one side 38 of the die assembly 14 to
another side 48 of the die assembly 14. Each end of the die cavity 44 forms an
opening 52 in a respective side 38, 48 of the die assembly 14.
[00014] Each slot 28 can be formed in the lower die member 21 by
machining or other suitable method. Each slot 28 is keyhole-shaped and is
formed
in an upwardly projecting structure 59 integrally fornied on the lower die
member
21. Each slot 28 includes a relatively wider portion 60 and a relatively
narrower
portion 62. The fastener 24, as shown in FIG. 4, is inserted into the slot 28
through a
keyhole-shaped top opening 64 in the slot 28. As shown in FIG. 5, the wider
portion
62 of each slot 28 is configured to receive the head 33 and shoulder portions
32 of a
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respective fastener 24. Each slot 28 includes transversely extending wall
surfaces 58
that abuttingly engage the annular surface 56 of the shoulder portion 32 of
the
fastener 24 when the nut 36 is tightened. Thus, each slot 28 is configured to
receive
and abuttingly engage the shoulder portion 32 as the fastener 24 is inserted
into the
slot 28 in a direction that is transverse to the longitudinal axis of the
fastener. When
the upper die member 19 is placed on the lower die member 21, the upper die
member 19 covers the top opening 64 into each slot 28 to retain each fastener
24 in
its associated slot 28. Also, separate covers can be used to cover the
connection
between the fasteners 24 and the slots 28, such as metal plates that attach
directly to
the lower die member 21.
[00015] Another illustrative embodiment of a slot 68 is shown in
FIG. 6. Slot 68 is provided by a pair of upwardly projecting integral wall
structures
70, 72 integrally formed on a lower die member 67. The shoulder portion 32 of
the
head 33 abuttingly engages surfaces 74, 76 on the wall structures 70, 72,
respectively, when a fastener 24 is disposed in the slot 68. A transversely
extending
groove 78 is formed adjacent the wall structures 70, 72 and receives a portion
of the
head 33 of the fastener 24. The embodiment of FIG. 6 permits greater leeway in
the
initial positioning of the head 33 when positioning the fastener 24 in slot
68. When
an upper die member is placed on the lower die member 67, the upper die member
67 covers the top opening of the slot 68. Also, separate covers can be used to
cover
the connection between the fasteners 24 and the slots 68, such as metal plates
that
attach directly to the lower die member 67. Except for the configuration of
slot 68,
the die assembly of lower die 67 and its corresponding hydroforming press
function
in a mamler substantially identical to that described above with respect to
the
embodiment of FIG. 5.
[00016] It can be appreciated that the positioning of an upper die
member in covering relation over a slot in a lower die member such as slot 28
or slot
68 is not required to maintain a fastener assembly in engagement with the slot
and
therefore in releasably coupled engagement with the die assembly. Thus, the
die
assembly 14 can be opened and closed, for example, to place a blank inside the
die
assembly or to remove a hydroformed member from the die assembly.
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[00017] The hydroforming presses 16, 18 are of identical construction
to one another in the illustrative embodiment, although this is not required,
so the
following discussion will focus primarily on press 16, but the discussion
applies
equally to press 18. Each hydroforming press 16, 18 includes a hydraulically
driven,
tube end-engaging structure 20 and a press housing 22. The present invention
is
primarily concerned with the manner in which each hydraulic press 18, 20 and
each
press housing 22 is removably coupled to the die assembly 14. The details of
the
construction and operation of each of the hydroforming presses 16, 18 and of
the
components thereof, including the tube engaging structures 20, the pressure
intensifying structures, and the hydraulic power source, are not considered in
detail
herein but can be as described in commonly assigned United States Patent No.
6,014,879 to Jaekel et al., the entirety of which is hereby incorporated by
reference
into the present application for all material disclosed therein. Generally,
the tube
engaging structure 20 is mounted in the press housing 22 for longitudinal
movement
with respect to the die assembly 14 and the press housing 22. The press
housing 22
is removably mounted on the die assembly 14 by fasteners 24 in a manner
described
below (see FIGS. 2 and 3, for example).
[00018] Each press housing 22 includes a hydraulic cylinder as is
generally known in the art and may be constructed to support and guide the
associated tube engaging structure 20 as its specially adapted piston and to
align the
associated tube engaging structure 20 with the adjacent opening 52 of the die
cavity
44 so that each tube engaging structure 20 enters and abuttingly engages a
respective
end of the tubular blank 12 within the die cavity 44.
[00019] FIGS. 7 and 8 show, schematically and in isolation, the press
housing 22 and a fastener assembly 37 loosely engaged therewith. The press
housing 22 is in a configuration to be mounted on a side of the die assembly
14.
[00020] The tube engaging structure 20 is operatively connected to a
hydraulically driven pressure intensifying structure such as a hydraulic
cylinder, and
to a hydraulic power source. During a hydroforming operation, the tube
engaging
structure 20 seals an end of the blank 12 and transmits a hydroforming fluid
received
from the fluid source through a fluid supplying passageway 26 into the
interior of
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the blank 12. The pressure intensifying structure increases the pressure of
the
hydrofonning fluid in the interior of the blank 12 which expands the blank 12
into
conformity with die surfaces within the die assembly 14. The tube engaging
structure 20 is movable in a longitudinal direction under hydraulic power with
respect to the press housing 22 and the die assembly 14 to longitudinally
compress
the blank 12 during hydroforming.
[00021] The manner in which each press housing 22 is removably
coupled to the die assembly 14 can be understood from FIGS. 1-5. The lower die
member 21 includes a pair of slots 28 on each side thereof. A pair of
fasteners 24
removably couple each press housing 22 to a pair of slots 28 on the die
assembly 14.
A pair of spacers 29 are disposed between each press housing 22 and the die
assembly 14 and are operable to space the press housing 22 from the die
assembly
14 and to align the press housing 22 with the die assembly 14. The fasteners
24 are
structurally identical to one another and the spacers 29 are structurally
identical to
one another in the illustrated embodiment, although this is not required by
the
invention. Therefore, the fasteners 24 and associated structures and the
spacers 29
are identified respectively by identical reference numbers.
[00022] Each fastener 24 includes a grip portion in the form of a
longitudinally extending shaft 30 with a threaded end 31 and includes a
shoulder
portion 32 in the form of a head 33 mounted on the shaft 30. Each spacer 29 is
a
tubular metallic sleeve that is mounted around the shaft 30 of each fastener
24. Each
fastener 24 extends through an aperture 34 in the press housing 22 and is
secured to
the press housing 22 by a locking crown nut 36. Although fastener 24 is
illustrated
as being tightened by nut 36, any appropriate fastener and tightening
mechanism can
be used so long as it sufficiently and securely tightens the presses 16 and
18. Each
fastener 24 loosely fits within an aperture 34 in the housing 22, although
this is not a
requirement of the invention. That is, the inner diameter of the aperture 34
is
sufficiently larger than the outer diameter of the fastener 24 to allow
transverse
movement of the fastener 24 with respect to the aperture 34. Each fastener 24,
nut
36 and spacer 29 comprises a fastener assembly 37.
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[00023] As shown in FIG. 4, the head 33 and the shaft 30 of each
fastener 24 are separate structures in the illustrative embodiment (see FIG.
4). The
head 33 is a cylindrical structure that is threadedly engaged with the shaft
portion
31. Both the head 33 and the shaft 30 of the fastener 24 are integral
structures that
are constructed of a metallic material such as steel. An underside of the head
33
provides an annular surface 56 which forms the shoulder portion 32 of the
fastener
24. Of course, fastener 24 can be made of various configurations, such as a
one-
piece, integral member, and other types of fasteners that achieve the same
results of
being appropriately inserted into a die half and then tightened can be
employed.
[00024] With reference again to FIGS. 1-3, 7 and 8, each spacer 29 is
constructed of a metallic material such as steel and abuttingly engages
surfaces on
the press housing 22 and the die assembly 14 when the fastener assemblies 37
are
tightened. The spacers 29 are operable to align the central passageway 54 of
the
press housing 22 with an adjacent end portion of the die cavity 44 and to
space the
press housing 22 a predetermined distance from the die assembly 14.
[00025] The press housing 22, the fastener 24, the spacer 29, and the
nut 36 can be heavy and cumbersome depending on the size of the die assembly
and
14 and the blank 12 to be hydroformed. For example, the shaft 30 portion of
each
fastener 24 may weight 50-75 pounds and each locking crown nut 36 may weight
50-75 pounds. The present invention simplifies handling of these and other
components because the fastener assemblies 37 does not have be removed from a
press housing 22 once installed therein. More specifically, prior to
installation of a
press housing 22 on a side of the die assembly 14, each fastener 24 is loosely
held
on the press housing 22 by a nut 36. The spacers 29 are loosely disposed on
the
shafts 30. A press housing 22 is lifted above the lower die member 21 and then
lowered such that the pair of fasteners 24 on the press housing 22 move into a
pair of
slots 28 on a side of the lower die member 21 as seen in FIGS. 1-3 and 5 as
the
spacers 29 are provided with sufficient room to move along the shaft 30 of the
fastener 24 to provide enough clearance between the head 32 and the spacer 29
to
permit the wall of the slot 28 to pass therebetween. When the press housing 22
is
mounted on the die assembly 14, the pair of spacers 29 are positioned between
a side
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38 of the die assembly 14 and a side 40 of the press housing 22. Each nut 36
is
tightened to a specified tightness to secure the press housing 22 to the die
assembly
14. The press housing 22 can be removed by loosening each nut 36 and lifting
the
fasteners 24 out of the slots 28.
[00026] Because the fastener assemblies 37 remain loosely attached to
the press housing 22 as the press housing 22 is being installed on or removed
from
the die assembly 14, there are no separate parts during installation, removal,
handling, or subsequent reinstallation of the press housing 22. The fastener
assemblies 37 enable a single worker to quickly and safely install, remove,
handle,
and reinstall a press housing 22 on a die assembly 14. The individual
components
that comprise the fastener assemblies 37 do not have to be handled separately
during
installation and removal of a press housing 22 from a die assembly 14.
Operation
[00027] To couple hydroforming presses 16, 18 to the lower die
member 21 of the die assembly 14, the die assembly 14 is opened so the upper
die
member 19 is spaced from the lower die member 21 to expose the slots 28 in the
lower die member 21. Each press housing 22 and the associated fastener
assemblies
37 are lifted above the lower die member 21 (by, for example, a single worker
operating a crane) and positioned so that the fastener assemblies 37 are
aligned with
the associated slots 28.
[00028] The spacers 29 are spaced from the shoulder portion 32 so
that the head 33 of each fastener assembly 37 and the adjacent shaft 30
portion can
be lowered into the wide and narrow portions 60, 62, respectively, of the
slots 28.
The fastener assemblies 37 of each press housing 22 are lowered into
respective
slots 28, thereby positioning the shoulder 32 of each fastener 24 within a
slot 28 in
the lower die member 21 by moving the shoulder 32 and the fastener 24 in a
direction that is substantially transverse to the longitudinal axis of the
associated
fastener 24.
[00029] Each spacer 29 is positioned generally between the press
housing 22 and a side of the die assembly 14 when the fastener assemblies 37
are in
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their respective slots 28. The fastener assemblies 37 can be tightened by
tightening
each nut 36 with an appropriate tool. The die assembly 14 may be moved into
its
closed position before tightening each nut 36, although this is not required
by the
invention. Thus, each nut 36 can be tightened prior to closing the die
assembly 14.
[00030] A tube engaging structure 20 of the hydroforming presses 16,
18 is moved into each press housing 22 once the press housings 22 are secured
to the
die assembly 14. A blank 12 is placed in the die assembly 14 and is subj ect
to
hydroforming. The press housings 22 can remain attached to the lower die
member
21 of the die assembly 14 as the die assembly 14 is opened and closed. That
is, each
press housing 22 can remain attached to the lower die member 21 until the
fastener
assemblies 37 are loosened by a worker.
[00031] Each press housing 22 can be removed by following
essentially the reverse procedure. That is, the nut 36 of each fastener
assembly 37
can be loosened and the associated press housing 22 can be lifted away from
the
lower die member 21 with the fastener assemblies 37 attached to the press
housing
22. The fastener assemblies are lifted out of the lower die member 21 or 67 in
a
direction that is substantially transverse to the longitudinal axis of the
fasteners 24.
Because the fastener assemblies 37 are coupled to the press housing 22, the
fastener
assemblies 37 provide a way for a single worker to quickly change which press
housing 22 is coupled to a particularly die assembly. A die assembly can be
quickly
reconfigured by changing the particular press housings 22 that are coupled
thereto so
that a wide range of different tube engaging structures (or "hydraulic
cylinders") can
be used on a particular die assembly. Also, it permits housing 22 to be used
with
different die assemblies. Thus, fewer sets of hydraulic cylinders are thus
required
which reduces manufacturing costs.
[00032] It can be appreciated that the illustrative embodiments of the
present invention are intended to illustrate principles of the invention and
are not
intended to limit the scope of the invention to the specific embodiments
illustrated.
Many other structures could be constructed to provide a spacing function,
therefore
many variations are contemplated. For example, although the spacers are
mounted
on the fasteners, it can be understood that this specific construction is not
required
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by the invention. In other embodiments, the spacers can be provided by one or
more
members that are spaced from the fasteners and are permanently or removably
attached to the press housing or to the die assembly.
[00033] Thus, while the invention has been disclosed and described
with reference with a limited number of embodiments, it will be apparent that
variations and modifications may be made thereto without departure from the
spirit
and scope of the invention and various other modifications may occur to those
skilled in the art. Therefore, the following claims are intended to cover
modifications, variations, and equivalents thereof.
